.big{

    width: 100%;
    height: 20%;
    background-color: #ffffff;
}
.box1{
    height: 40px;
    line-height: 40px;
}
input{
    margin-left: 20px;
    width: 90%;
    height: 20px;
}
label{
    margin-left: 20px;
}
.box3{
    height: 50px;
    line-height: 50px;
}
.box3 select{
    width: 200px;
}
.box3 label{
    margin-left: 50px;
}
span{
    margin-left: 10px;
}
#class{
    margin-right: 20px;
}
button{

    height: 25px;
    line-height: 25px;
    width: 200px;
}
.ex{
    margin-left: 200px;
}
button:hover{
    background-color: #a6b5cc;
}